1. Field of the Invention
The invention relates generally to electrical motors, and more particularly to systems and methods for processing power provided to downhole electrical systems such as electric submersible pump motors to increase the power factor of the supplied power at the motor.
2. Related Art
Oil and gas are commonly produced from geological formations through wells that may be tens of thousands of feet deep. Because the naturally existing pressure in the wells may be insufficient to force the oil and gas out of the wells, artificial lift systems such as electric submersible pumps (ESP's) are often used to extract the oil and gas from the wells.
ESP systems and other downhole equipment are quite expensive. The power cables that are used to supply power to ESP systems are also costly, and may even be more expensive than the ESP systems themselves. Because this equipment is so expensive, it is important that the equipment be as reliable as possible.
One of the factors that has the greatest impact on the reliability of downhole motors is heat. Generally speaking, the more heat the motor is subjected to, the less reliable the motor will be. This problem is aggravated by the fact that the downhole environment itself is typically already very hot. It is therefore important to take heat into consideration when designing downhole equipment such as ESP motors.
One way this problem was addressed in conventional systems was by using materials in the motors that are suitable for operation in high temperatures. The motors were also designed to be as efficient as possible, so as to generate the least amount of heat possible. While these approaches are useful, it would be desirable to provide alternative means to address the effects of heat on a downhole motor by considering a factor that has been largely ignored—the power factor at the motor.